Nanometer-Scale Wires of Monolayer Height Alkanethiols on AlGaAs/GaAs Heterostructures by Selective Chemisorption

Self-assembled nanometer-scale wires (SANWs) composed of octadecylthiol [ODT, CH3(CH2)17SH] have been selectively formed on the GaAs surface of an AlGaAs/GaAs heterostructure. The sample grown by metal organic chemical vapor deposition (MOCVD) was cleaved to expose the AlGaAs/GaAs heterostructure in a solution containing the ODT molecules. Both surface properties and morphology of these wires have been investigated simultaneously by scanning probe microscopy. SANWs as narrow as 10 nm in width and ∼1.0 nm in height were observed. The inability to form an ODT monolayer on the AlGaAs surface was attributed to the formation of an oxide layer.